According to the generally known state of the art, holding devices of interest at this point may be attached to the fuselage cell structure by means of screw connections. To this end, at least one fastening bore into the fuselage cell structure would need to be incorporated for each of the holding devices that are to be attached, in which a basic element of the holding device may be fastened by means of a fastening element.
The multitude of fastening bores leads to a static weakening of the fuselage cell structure and, in addition, causes corrosion problems within the area of the bearing stress, which must be prevented by extensive corrosion protection measures such as, for example, sealing of the bearings applying suitable materials. Furthermore, every area exposed to bearing stress creates a preferred initiation point for fatigue cracks, the discovery and removal of which requires an increased inspection and maintenance effort over the whole lifecycle interval of the aircraft. In addition, any drilling of a fastening borehole taken as an individual process is quite extensive with regard to process technology, as the positioning of the usually manual drilling devices is usually carried out by using large-format master plates. The resulting drilling chips must also be carefully removed from the fuselage cell structure by means of suction to prevent short circuits and any additional corrosion problems.
Therefore, DE 10 2007 061 425 A1 discloses a holding device for attaching a fixture at a fuselage cell structure of an aircraft, which may be affixed laterally to the fuselage cell structure without applying fastening bores. To this end, the crossing point between a stringer and a rib is used, into which a connecting angle of the holding device may be clamped. The holding device is embodied in two parts and comprises a lower part and an upper part, which may be connected thereto. The lower part may be slid onto the connecting angle. By fitting the upper part onto the lower part, the holding device assumes its fixed position after being fastened at the crossing point. Final fastening and positioning is obtained by connecting the holding device to a transverse circuit carrier by means of an expanding pin.
DE 10 2008 041 259 A1 discloses another solution to provide a connection without fastening means of a holding device at the fuselage cell structure of an aircraft, which is based on adhesive bonding. An adhesive holder comprises a basic body, which is connectible to an attachment. The basic body and the attachment are each formed in one piece of a metallic material. At least three lugs are arranged at the basic body to provide an adhesive connection at the fuselage cell structure. In doing so, at least two lugs are positioned at one connection level, and at least one further lug is positioned at a second connection level to allow fastening at an edge of the structural component. To allow fastening at plane structural components, all three lugs are arranged at one connection level. As a consequence of the presence of at least three lugs, the adhesive holder is damage tolerant such that even in the event of failure of two adhesive lugs no loss of functionality occurs. However, the load-bearing capacity of said adhesive holder is limited and, therefore, not suitable for all kinds of fixtures.
An embodiment of the present invention provides a holding device for attachment of at least one fixture at a fuselage cell structure of an aircraft not requiring any bore holes, which can be manufactured in a simple manner and which resists the high stress caused by the fixture.